Network Working Group G. Bossert
Request for Comments: 2084 S. Cooper
Category: Informational Silicon Graphics Inc.
W. Drummond
IEEE, Inc.
January 1997
Considerations for Web Transaction Security
Status of this Memo
This memo provides information for the Internet community. This memo
does not specify an Internet standard of any kind. Distribution of
this memo is unlimited.
Abstract
This document specifies the requirements for the provision of
security services to the HyperText Transport Protocol. These
services include confidentiality, integrity, user authentication, and
authentication of servers/services, including proxied or gatewayed
services. Such services may be provided as extensions to HTTP, or as
an encapsulating security protocol. Secondary requirements include
ease of integration and support of multiple mechanisms for providing
these services.
1. Introduction
The use of the HyperText Transport Protocol [1] to provide
specialized or commercial services and personal or private data
necessitates the development of secure versions that include privacy
and authentication services. Such services may be provided as
extensions to HTTP, or as encapsulating security protocols; for the
purposes of this document, all such enhancements will be referred to
as WTS.
In this document, we specify the requirements for WTS, with the
intent of codifying perceived Internet-wide needs, along with
existing practice, in a way that aids in the evaluation and
development of such protocols.
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WTS is an enhancement to an object transport protocol. As such, it
does not provide independent certification of documents or other data
objects outside of the scope of the transfer of said objects. In
addition, security at the WTS layer is independent of and orthogonal
to security services provided at underlying network layers. It is
envisioned that WTS may coexist in a single transaction with such
mechanisms, each providing security services at the appropriate
level, with at worst some redundancy of service.
1.1 Terminology
This following terms have specific meaning in the context of this
document. The HTTP specification [1] defines additional useful
terms.
Transaction:
A complete HTTP action, consisting of a request from the
client and a response from the server.
Gatewayed Service:
A service accessed, via HTTP or an alternate protocol, by the
HTTP server on behalf of the client.
Mechanism:
An specific implementation of a protocol or related subset of
features of a protocol.
2. General Requirements
WTS must define the following services. These services must be
provided independently of each other and support the needs of proxies
and intermediaries
o Confidentiality of the HTTP request and/or response.
o Data origin authentication and data integrity of the HTTP request
and/or response.
o Non-repudiability of origin for the request and/or response.
o Transmission freshness of request and/or response.
o Ease of integration with other features of HTTP.
o Support of multiple mechanisms for the above services.
3. Confidentiality
WTS must be able to provide confidentiality for both requests and
responses. Note: because the identity of the object being requested
is potentially sensitive, the URI of the request should be
confidential; this is particularly critical in the common case of
form data or other user input being passed in the URI.
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4. Service Authentication
WTS should support the authentication of gatewayed services to the
client.
WTS should support the authentication of the origin HTTP server or
gatewayed services regardless of intermediary proxy or caching
servers.
To allow user privacy, WTS must support service authentication with
user anonymity.
Because the identity of the object being requested is potentially
sensitive, service authentication should occur before any part of the
request, including the URI of the requested object, is passed. In
cases where the authentication process depends on the URI (or other
header data) of the request, such as gatewayed services, the minimum
necessary information to identify the entity to be authenticated
should be passed.
5. User Authentication
WTS must support the authentication of the client to the server.
WTS should support the authentication of the client to gatewayed
services.
WTS should support the authentication of the client to the origin
HTTP server regardless of intermediary proxy servers.
6. Integrity
WTS must provide assurance of the integrity of the HTTP transaction,
including the HTTP headers and data objects of both client requests
and server responses.
7. Integration
In order to support integration with current and future versions of
HTTP, and to provide extendibility and independence of development,
the secure services provided by WTS must be orthogonal to and
independent of other services provided by HTTP.
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In accordance with the layered model of network protocols, WTS must
be:
o independent of the content or nature of data objects being
transported although special attention to reference integrity of
hyperlinked objects may be appropriate
o implementable over a variety of connection schemes and
underlying transport protocols
8. Multiple Mechanisms
WTS must be compatible with multiple mechanisms for authentication
and encryption. Support for multiple mechanisms is required for a
number of reasons:
o Accommodation of variations in site policies, including those
due to external restrictions on the availability of
cryptographic technologies.
o Support for a variety of applications and gatewayed services.
o Support for parallel implementations within and across
administrative domains.
o Accomodation of application-specific performance/security
tradeoffs.
To allow interoperability across domains, and to support the
transition to new/upgraded mechanisms, WTS should provide negotiation
of authentication and encryption mechanisms.
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References
[1] Berners-Lee, T., Fielding, R., and H. Frystyk Nielsen,
"Hypertext Transfer Protocol -- HTTP/1.0", RFC 1945,
May 1996.
[2] G. Bossert, S. Cooper, W. Drummond. "Requirements of Secure
Object Transfer Protocols", Work in Progress
, March 1995.
The revision history of this document can be located at
Acknowledgments
This document is a product of the IETF WTS working group. The
working group uses the wts-wg@postofc.corp.sgi.com mailing list for
discussion. The subscription address is wts-wg-
request@postofc.corp.sgi.com.
Eric Rescorla of Terisa provided valuable comments
on an early draft of a document called "Requirements of Secure Object
Transfer" [2], a principal influence on this document.
Security Considerations
As noted above.
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Authors' Addresses
Greg Bossert
Silicon Graphics, Inc. MS 15-7
2011 North Shoreline Blvd.
Mountain View, CA 94043-1389
USA
EMail: bossert@corp.sgi.com
Simon Cooper
Silicon Graphics, Inc. MS 15-7
2011 North Shoreline Blvd.
Mountain View, CA 94043-1389
USA
EMail: sc@corp.sgi.com
Walt Drummond
Institute of Electrical and Electronics Engineers, Inc.
445 Hoes Lane
Piscataway, NJ 08855-1331
USA
Phone: 908-562-6545
Fax: 908-562-1727
EMail: drummond@ieee.org
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